1. Field of the Invention
The present invention relates to phase shifter circuits and more particularly to switchable high pass/low pass realizations of such circuits.
2. Description of the Prior Art
The design of phase shifters using field effect transistors ("FET") and high pass/low pass filter sections is well known. See, for example, Garver, "Broad-Band Diode Phase Shifters," IEEE Transactions MTT, pp. 314-23 (May 1972). Such devices have particular importance in microwave transmit/receive modules. It is of significant importance to have such devices be as small and low loss as possible. High pass/low pass filters have provided the smallest realization, however current state of the art uses five switching devices in such circuits. Smaller realization would result in smaller die size, reduced losses and higher yields, which in turn results in a lower cost product.